Express your answer as a mixed number simplified to lowest terms. $20\dfrac{4}{6}-5\dfrac{9}{10} = {?}$
Explanation: Simplify each fraction. $= {20\dfrac{2}{3}} - {5\dfrac{9}{10}}$ Find a common denominator for the fractions: $= {20\dfrac{20}{30}}-{5\dfrac{27}{30}}$ Convert ${20\dfrac{20}{30}}$ to ${19 + \dfrac{30}{30} + \dfrac{20}{30}}$ So the problem becomes: ${19\dfrac{50}{30}}-{5\dfrac{27}{30}}$ Separate the whole numbers from the fractional parts: $= {19} + {\dfrac{50}{30}} - {5} - {\dfrac{27}{30}}$ Bring the whole numbers together and the fractions together: $= {19} - {5} + {\dfrac{50}{30}} - {\dfrac{27}{30}}$ Subtract the whole numbers: $=14 + {\dfrac{50}{30}} - {\dfrac{27}{30}}$ Subtract the fractions: $= 14+\dfrac{23}{30}$ Combine the whole and fractional parts into a mixed number: $= 14\dfrac{23}{30}$